Science
Stage 9
Paper 2
Cambridge Lower Secondary Progression Test
Mark Scheme
3146_02_MS_4RP
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2023
3146/02
Science Stage 9 Paper 2 Mark Scheme
2023
General guidelines on marking
Many descriptive answers can be expressed in a variety of ways. Professional judgement can be
used in these cases, providing it matches the marking points and further information in the mark
scheme.
Answers may have words spelt incorrectly. Credit is normally given for phonetically correct answers,
unless the word has a scientifically different meaning. For example, where the answer should be
antennae, credit will be given for antena but not for anthen (too close to anther).
Only the science is being assessed, so answers do not need to be grammatically correct.
Significant figures will be indicated in the question or in the mark scheme.
Unless specified all marking points are independent.
Annotations and abbreviations
/ or
alternate responses for the same marking point
( ) brackets
the words or units in brackets do not need to be stated, for example, (recycles or
releases or provides) minerals = minerals scores the mark
underline
exact word is required
Accept
an acceptable response
Do not accept
indicates an incorrect response that would contradict another otherwise correct
alternative
Ignore
indicates an irrelevant answer that is not creditworthy. Full marks can still be
achieved even with answers that are ignored.
Note
provides extra information when necessary
ecf
error carried forward; marks are awarded if an incorrect response has been carried
forward from earlier working provided the subsequent working is correct
ora
or reverse argument; for example, as mass increases, volume increases could be
written as mass decreases, volume decreases
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Page 2 of 12
3146/02
Question
Science Stage 9 Paper 2 Mark Scheme
Answer
Marks
1
2023
Further Information
4 each correct answer = 1 mark
when nitrate ions and magnesium ions are both present the
(barley seedlings) have the greatest dry mass
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nitrate ions have a greater effect on the dry mass than
magnesium ions / ora
Accept the seedling with just nitrate ions grows
more than the seedling with just magnesium ions
/ ora
nitrate ions are needed to make proteins
Accept nitrate ions are needed to make DNA or
amino acids
magnesium ions are needed to make chlorophyll
Accept magnesium ions are needed for
photosynthesis
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3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
2023
Marks
Further Information
2(a)(i)
concentration (of acid)
1
2(a)(ii)
(dependent variable) volume of gas
1 both answers correct for the mark
(how it is measured) water level in measuring cylinder
2(a)(iii)
1 both answers correct for the mark
any two from
Do not accept (same) concentration of acid
(same) mass (of calcium carbonate)
(same) particle size or same surface area (of calcium
carbonate)
(same) temperature
(same) volume (of acid)
2 each correct answer = 1 mark
2(b)
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(safety risk) acid is corrosive
Accept acid can burn skin or eyes or acid can
irritate skin or eyes or acid can harm skin or eyes
(how to control the risk) wear eye protection
Accept wear gloves
Page 4 of 12
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
2023
Marks
Further Information
3(a)
100 (Hz)
1 no tolerance
3(b)
90 000 (Hz)
1 Accept between 80 000 and 99 000 (Hz)
or
(range is from) 1000 (Hz) to 90 000 (Hz)
Accept between 80 000 and 99 000 (Hz) for the
value of 90 000 (Hz)
no tolerance on the value of 1000 (Hz)
3(c)(i)
increases the pitch
1 Accept higher pitch
Note answer must be comparative
3(c)(ii)
increases the loudness or increases the volume
1 Accept louder sound
Note answer must be comparative
3(d)(i)
4 (times)
1
3(d)(ii)
2 (times)
1 Accept waveform A has twice the frequency of
waveform B
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Page 5 of 12
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
2023
Marks
Further Information
4(a)(i)
decreases
1
4(a)(ii)
line of best fit extended to the x-axis
2 each correct answer = 1 mark
correct year read from the line to the nearest year
4(a)(iii)
2 each correct answer = 1 mark
any two from
variation within the species
(idea of) best adapted survive or (idea of) competition
Accept survival of the fittest
advantageous adaptions passed on to offspring
4(b)(i)
(increases) there are more females to produce offspring
2 each correct explanation = 1 mark
(decreases) there will be fewer males to mate with the
females
4(b)(ii)
(effect on the population) decreases (no marks)
(reason 1) (idea of) the nesting sites will be flooded
(reason 2) the offspring will drown or the offspring will have
insufficient oxygen to respire
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Page 6 of 12
2 increase = 0 marks for the question
each correct reason= 1 mark
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
Marks
2023
Further Information
3 Accept 8.9 with or without working = 3 marks
5(a)
Accept 8.947368 with or without working = 2
marks
correct substitution of numbers into formula or 340 ÷ 38
correct construction of formula
mass ÷ volume or 340 ÷ 38
correct division, e.g. 8.947368
correct division using their values from
substitution
Accept truncated answers or incorrect rounding
correct answer 8.9
2 each correct answer = 1 mark
5(b)
(substance) B
(explanation) (idea of) lowest density or density much lower
than others or has a very low density
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Page 7 of 12
Accept density of gas usually less than solids or
liquids
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
6
Answer
Marks
2023
Further Information
3 each correct answer = 1 mark
any three from
(water) particles gain energy from skin
Accept molecules for particles throughout
more energetic (water) particles escape (from surface of
skin or to air)
Accept faster molecules escape
less energetic (water) particles remain (on skin)
Accept slower (water) particles remain
thermal energy transfers from body or skin
Accept heat for thermal energy
Accept evaporation is endothermic as an extra
marking point
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Page 8 of 12
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
7(a)
combustion
2023
Marks
carbohydrate moves
from one organism to
another organism
Further Information
4 all five correct = 4 marks
three or four correct = 3 marks
two correct = 2 marks
7(b)
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decomposition
the breakdown of
dead and decaying
waste material
feeding
the burning of fossil
fuels
photosynthesis
the release of energy
from the breakdown
of glucose
respiration
the formation of
glucose and oxygen
by green plants
photosynthesis
one correct = 1 mark
if two lines from one process to different
descriptions = 0 marks for that process
1
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3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
8(a)
Answer
2023
Marks
tectonic plates
Further Information
1
1 arrow heads must be in the correct direction on all
arrows drawn
8(b)(i)
crust
mantle
1 arrow heads must be in the correct direction on all
arrows drawn
8(b)(ii)
Accept a full convection current
crust
mantle
8(c)(i)
(idea of) they follow the same pattern or active volcanoes
are found where the boundaries of the floating rocks or
tectonics plates are located
1
8(c)(ii)
no boundaries near South Africa
1
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Page 10 of 12
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
Marks
Further Information
9(a)
copper nitrate
1
9(b)
(idea that) mass of reactants is the same as mass of
products or no loss or gain of mass during the reaction
1
9(c)
2 each correct answer = 1 mark
(name) covalent bond
(description) shared pair of electrons
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2023
Page 11 of 12
3146/02
Science Stage 9 Paper 2 Mark Scheme
Question
Answer
2023
Marks
Further Information
2 each correct answer = 1 mark
10(a)
(pump) cell(s) or battery or power supply
(hot water) charge or electrons or current
Ignore wire
10(b)
2 each correct answer = 1 mark
any one strength from
both water and current are not ‘used up’ as they pass
around the pipes/circuit
there is the same amount of water or current at all points
same rate of flow of water or current or charge at all points
any one limitation from
you cannot see what is happening to the water in the pipes
it takes time for the water to reach the radiator
it takes time for radiator to get hot (but the lamp turns on
straight away)
water can leak (out of pipes) but current cannot leak (out of
wires)
Accept (idea that) the pump requires energy to
work but the cell provides the electrical energy
Accept looks like a circuit so easy to visualise
Accept to help explain a difficult idea, e.g. current
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